As a system for determining a user position, for example, a system for detecting the user position by exchanging positional information via a radio wave/optical beacon or the like is known. However, when the user position is determined at indoor, there has been a problem of an extremely high infrastructure costs to install a large number of radio waves/optical beacons or the like.
For example, PTL1 discloses a mobile object that includes a camera for capturing image of ceiling surface, stores an image of ceiling that is captured in advance together with the positional information as teaching image information, compares the teaching image information with the captured image, and detects a position of the mobile object.